[Linux-kernel-mentees] [PATCH v1 1/3] amd64-agp: use generic power management

[Vaibhav Gupta <vaibhavgupta40@gmail.com>]

Drivers using legacy PM have to manage PCI states and device's PM states
themselves. They also need to take care of configuration registers.

With improved and powerful support of generic PM, PCI Core takes care of
above mentioned, device-independent, jobs.

This driver makes use of PCI helper functions like
pci_save/restore_state() and pci_set_power_state() to do required
operations. In generic mode, they are no longer needed.

Change function parameter in .resume() to "struct device*" type. Use
to_pci_dev() to get "struct pci_dev*" variable.

After upgrading, .suspend() became an empty-body function, hence defined as
NULL.

Compile-tested only.

Signed-off-by: Vaibhav Gupta <vaibhavgupta40@gmail.com>
---
 drivers/char/agp/amd64-agp.c | 24 ++++++------------------
 1 file changed, 6 insertions(+), 18 deletions(-)

diff --git a/drivers/char/agp/amd64-agp.c b/drivers/char/agp/amd64-agp.c
index b40edae32817..57fdcc61f88a 100644
--- a/drivers/char/agp/amd64-agp.c
+++ b/drivers/char/agp/amd64-agp.c
@@ -588,20 +588,11 @@ static void agp_amd64_remove(struct pci_dev *pdev)
 	agp_bridges_found--;
 }
 
-#ifdef CONFIG_PM
+#define agp_amd64_suspend NULL
 
-static int agp_amd64_suspend(struct pci_dev *pdev, pm_message_t state)
+static int __maybe_unused agp_amd64_resume(struct device *dev)
 {
-	pci_save_state(pdev);
-	pci_set_power_state(pdev, pci_choose_state(pdev, state));
-
-	return 0;
-}
-
-static int agp_amd64_resume(struct pci_dev *pdev)
-{
-	pci_set_power_state(pdev, PCI_D0);
-	pci_restore_state(pdev);
+	struct pci_dev *pdev = to_pci_dev(dev);
 
 	if (pdev->vendor == PCI_VENDOR_ID_NVIDIA)
 		nforce3_agp_init(pdev);
@@ -609,8 +600,6 @@ static int agp_amd64_resume(struct pci_dev *pdev)
 	return amd_8151_configure();
 }
 
-#endif /* CONFIG_PM */
-
 static const struct pci_device_id agp_amd64_pci_table[] = {
 	{
 	.class		= (PCI_CLASS_BRIDGE_HOST << 8),
@@ -738,15 +727,14 @@ static const struct pci_device_id agp_amd64_pci_promisc_table[] = {
 	{ }
 };
 
+static SIMPLE_DEV_PM_OPS(agp_amd64_pm_ops, agp_amd64_suspend, agp_amd64_resume);
+
 static struct pci_driver agp_amd64_pci_driver = {
 	.name		= "agpgart-amd64",
 	.id_table	= agp_amd64_pci_table,
 	.probe		= agp_amd64_probe,
 	.remove		= agp_amd64_remove,
-#ifdef CONFIG_PM
-	.suspend	= agp_amd64_suspend,
-	.resume		= agp_amd64_resume,
-#endif
+	.driver.pm	= &agp_amd64_pm_ops,
 };
 
 
-- 
2.27.0

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